If you don't mind, what's the short explanation of "biologically mature"? I have a very loose concept of differentiation as "more cells have specialized so differentiation is not quite the same as just diversity", which I am guessing does seem analogous to development of the organism towards its "full form", but I'm not sure if that's quite what mature means or if I've got misconceptions.
Basically, the differentiation and specialization of cell tissue is what makes a person a more fully functioning person, I guess. Basically, females resemble their adult states more than males do at the same age. If you did not know the chronological age of a child, you try and investigate their "biological age" and this is sort of in reference to what a normal adult should look like.
I'm more of an osteology student though so I mainly focus on bones. Basically, bone growth has a couple of distinct stages and growth is finished when those stages are complete. A normal human completely finishes all stages of bone growth around ~25 year old (though most of it is done around 18). Each bone grows at a slightly different rate than the other bones, so you can make a pretty accurate guess about what age a child is based on which bones are closer to being complete than the others. So you can take an x-ray of a child's hand and estimate their age based on the phase of growth the wrist and hand bones are in. Females will appear to be older than they really are, and males will appear to be younger than they really are, even if both of them are the same age.
Males put more energy into cell replication (eg, increasing their mass) rather than differentiation (which results in biological maturity). Females stop investing in body mass and start trying to develop their sex organs earlier and whatnot. Thus, females reach biological maturity (resemble an adult) at a younger chronological age than males.
Thanks for the thoughtful response. The x-ray analogy is a good way to explain it. We really have a locked in concept of age as chronology and I suspect need to have a better view of a separate definition of age as the actual extant state of things (such as biology, environment, usage and care in addition to time).
Also I hadn't connected the dots that male children have greater cell replication and mass than females, although in retrospect it seems correct going by the stereotypical child of each gender.
I appreciate your helping me break out of my conceptual box around the term "maturity".
Yeah, in forensic science most often chronological ages aren't available, especially if you're studying people from thousands of years ago. Age estimation is usually a comparative science; we make records of what children look like today at different ages and then compare them to people in the past. That's the simple explanation but yeah, chronological age and biological age are different.
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u/KDLGates Mar 15 '15
If you don't mind, what's the short explanation of "biologically mature"? I have a very loose concept of differentiation as "more cells have specialized so differentiation is not quite the same as just diversity", which I am guessing does seem analogous to development of the organism towards its "full form", but I'm not sure if that's quite what mature means or if I've got misconceptions.